CN101529122A

CN101529122A - Tensioner

Info

Publication number: CN101529122A
Application number: CNA2007800181024A
Authority: CN
Inventors: 郝闽椿; M·彼得拉什科; 刘克铭; O·斯蒂格尔曼
Original assignee: Gates Corp
Current assignee: Gates Corp
Priority date: 2006-03-29
Filing date: 2007-03-12
Publication date: 2009-09-09
Also published as: BRPI0710038A2; EP1999397A1; CA2647298A1; US20070249446A1; JP2009531634A; AU2007243819A1; WO2007126575A1; RU2008142768A; KR20080104078A

Abstract

A tensioner comprises a base, a pivot arm pivotally connected to the base, a pulley journalled to the pivot arm, a first biasing member disposed between the base and the pivot arm, the first biasing member imparting a spring force to the pivot arm over a first operating range, a second biasing member disposed between the base and the pivot arm, and the second biasing member imparting a spring force to the pivot arm at a predetermined pivot arm position, the predetermined pivot arm position disposed within the operating range and beyond which predetermined pivot arm position the second biasing member supplements a spring force of the first biasing member.

Description

Stretcher

Technical field

The present invention relates to a kind of stretcher, relate more specifically to a kind of stretcher with first spring and second spring, described second spring applies spring force to replenish the spring force of first spring in predetermined pivot arm position to pivot arm.

Background technique

Usually, stretcher comprises: provide the energy storage member of static torque (perhaps active force) output of equipment, such as spring; With the energy-absorbing member of modification equipment to the dynamic action force-responsive of outside input, for example damping mechanism of some type.Energy storage member and energy-absorbing member all work on the whole operating range of arm, rather than are selectively used in the operating range.Change along with the spring rate of the loading (limiting by the position of tensioner arms usually) of member and this member by the active force of energy storage member output with respect to the stretcher bottom.

Known stretcher with a plurality of energy storage members for example comprises the stretcher of two tension springs, and wherein the axis of these two springs is set on the same straight line.The spring of these conllinear provides two kinds of different functions, and each spring engages with the pivot arm operation continuously.First relates to the energy storage function.Second relates to the friction member that the damping deceleration loading device is provided or stops the motion of tensioner arms.

The representative of prior art is the U. S. Patent 4,826 of Ushio, 471 (1989), and it discloses a kind of automatic belt tensioner with spring structure, and wherein spring structure provides dual bias to the idle pulley against driving belt.This bias structure provides dual bias to the arm of this idle pulley of carrying, and described dual bias comprises by the biasing of reversing generation and the biasing that produced by the compression of spring structure.In one form, adopt a pair of bias spring, one of them is used to provide reverses biasing, and one is used to provide the compression biasing.In another form, single spring all exerts an influence to this dual bias effect.The compression bias structure comprises pair of cams, and these cams have the inclined surface that matches is realized pressure spring with the function that moves as I/ARM compression.

Summary of the invention

What need is a kind of stretcher with first spring and second spring, and second spring applies spring force to replenish the spring force of first spring to pivot arm on predetermined pivot arm position.The present invention has satisfied this needs.

Main aspect of the present invention provides a kind of stretcher with first spring and second spring, and second spring applies spring force to replenish the spring force of first spring to pivot arm on predetermined pivot arm position.

Others of the present invention will be pointed out or become apparent in following description of the present invention and accompanying drawing.

The present invention includes a kind of stretcher, it comprises: the bottom; The pivot arm that is connected with the bottom pivot; The belt pulley that is connected with the pivot arm axle journal; Be located at first biasing member between bottom and the pivot arm, described first biasing member applies spring force to pivot arm on first operating range; Be located at second biasing member between bottom and the pivot arm, and described second biasing member applies spring force to pivot arm on predetermined pivot arm position, the spring force that described predetermined pivot arm position is set in the operating range and second biasing member replenishes first biasing member when exceeding this predetermined pivot arm position.

Description of drawings

The accompanying drawing of incorporating this specification into and becoming this specification part shows the preferred embodiments of the present invention, and is used for explaining principle of the present invention with describing part.

Fig. 1 is the plan view of stretcher of the present invention;

Fig. 2 shows the wheel hub load of stretcher and the relation of displacement;

Fig. 3 is the schematic top plan view of stretcher, and it shows the valid function scope of pivot arm;

Fig. 4 is the decomposition view of stretcher;

Fig. 5 is the side view of torsion spring;

Fig. 6 (a) is the side cross-sectional view of second spring;

Fig. 6 (b) is the plan view of second spring;

Fig. 7 is the perspective view of damping boots;

Fig. 8 is the cross-sectional view of damping boots.

Embodiment

Fig. 1 is the plan view of stretcher of the present invention.Stretcher 100 comprises bottom 10.Bottom 10 comprises the hole 12 that receives the fastening piece (not shown), and described fastening piece is used for stretcher is attached to the assembly surface (not shown), for example on the motor.Fastening piece can comprise such as the such threaded fastener of bolt, perhaps can also comprise rivet, riveting post or adhesive.

Pivot arm 20 is sentenced pivotal rotating at pivot 21 mode links to each other with bottom 10.Belt pulley 30 is connected with pivot arm 20 axle journals at axostylus axostyle 31 places.Axostylus axostyle 31 can comprise any type of bolt well known in the art or bar.Belt pulley 30 engages power driving belt, for example belt in the accessory drive system.

Stretcher 100 comprises first spring 41 (referring to Fig. 4) and second spring 40 (referring to Fig. 4).41 places engage with bottom 10 second spring 40 at the joining portion.22 places engage with pivot arm 20 the other end of second spring 40 at the joining portion.Second spring comprises elastic material, such as two or more the combination in ethylene propylene diene rubber (EPDM), hydrogenated nitrile-butadiene rubber (HNBR), polyurethane, natural rubber, synthetic rubber or the above-mentioned substance.Spring 40 can also comprise compressible helical spring or torsion spring.

Fig. 2 shows the wheel hub load of stretcher and the relation of displacement.Auxiliary range B is outside normal operation range A.Auxiliary range B is a feature with the high spring rate of no preload.

The use of two

springs

40,41 provides two tensioner torque output areas.First moment of torsion output area is limited by spring 41, and illustrates with scope A in Fig. 2.Second moment of torsion output area is feature with the using of second spring 40 that intermittently engages as required, and illustrates with scope B in Fig. 2.In scope B, the summation of the moment of torsion that second moment of torsion output area is first spring 41 and the moment of torsion addition of second spring 40.When pivot arm 20 arrived the predetermined angle travel position, spring 40 replenished the spring force of spring 41.

Fig. 3 is the schematic top plan view of stretcher, and it shows the reached operating range of pivot arm.About radius R 1, the free arm position is about 117 °." free arm " is the residing position of rest of pivot arm under the promotion at spring not with belt lacing the time.Mean belt position (mean beltposition) is about 177 °, and load belt position is about 143 °.These numerical value just provide by way of example, and do not wish scope of the present invention is caused restriction.

" mean belt position " is the normal operating position of pivot arm.In that the position is identical with " load belt " position or on the position of angular deflection between these two positions, spring 40 engages with pivot arm 20 with " average belt ".

" load belt " position is for belt being installed in the position that on the tensioner pulleys pivot arm is moved to.In case load onto belt, pivot arm moves to mean belt position from load belt position usually.Load belt position is in usually and makes in the locational scope of spring 40 between compressing between part and compressing fully.Value range described here only is some examples, and does not wish described any scope is caused restriction.

Fig. 4 is the decomposition view of stretcher.Stretcher comprises the spring 41 that is contained in the bottom 10, and it is torsion spring in this embodiment.First end 42 of spring 41 links to each other with bottom 10.Second end 43 of spring 41 engages with damping boots 15.The internal surface 23 of damping boots 15 frictional engagement pivot arm 20.Damping boots 15 stop the swing of pivot arm 20.By pressure damping boots 15 are remained on the correct position from spring 41.

Base 11 on second spring, 40 engage base 10.Pin 14 is attached in spring 40 on the base 11.The other end of joining portion 22 contact springs 40.During operation, spring 40 is maintained between joining portion 22 and the base 11.The axis B-B of spring 40 is configured to the axis A-A approximate vertical with first spring 41.This also can be described as axis B-B be set at the axis A-A plane orthogonal on.

During operation, along with pivot arm 20 pivots, torsion spring 41 is subjected to twist compression, thereby applies spring force to the belt that engages with belt pulley 30.Dust guard 31 is used to the journal areas 33 that stops fragment to enter belt pulley 30.

Spring 40 is introduced the second elastomeric spring member, realizes in its normal operation range that acts on stretcher to operation.When arriving predetermined pivot arm position, spring 40 provides second spring force to strengthen the spring force of torsion spring 41.That is, second spring 40 or biasing member apply spring force to pivot arm on predetermined pivot arm position, the spring force that described predetermined pivot arm position is set in the operating range and second spring 40 replenishes first spring 41 when exceeding this position.When spring 40 engaged with pivot arm, the motion that spring 40 also can be pivot arm provided damping.

The low moment of torsion output of using single spring 41 to obtain adapts to the pivot arm response to normal belt input (thereby producing lower carrying and wheel hub fatigue load), yet extreme belt load input (with therefore extreme pivot arm movement) is adapted to by two springs, and second spring 40 is operated in the auxiliary operation scope.

The active force of spring 40 can be applied on the pivot arm on any position in the stroke range of pivot arm, and this means: spring 40 can contact joining portion 22 on any position in specifying the range of movement of using desired pivot arm 20.

The spring rate of spring 40 can be constant or gradual change, and this means: the function that spring rate can be used as axial compression displacement changes.Therefore pivot arm forces (and belt force) can have different springs of different spring rates by use adjusted.Spring 40 can comprise the common spring spiral winding spring of compression applications (for example be used to reverse or) or other elastic materials (comprising plastics, natural and synthetic rubber, for example polyurethane).Under the situation of using rubber or polymer, can radially support or supported spring 40 not, this means: spring is supported to prevent unsuitable lateral movement.

Spring 40 also provides " soft retainer " at the terminal point of pivot arm stroke range.In case pivot arm 20 is near the terminal point of its intended travel, pivot arm 20 bump " soft " springs 40, rather than collide hard retainer, this can produce noise and with the enough violent situation of the bump of base 11 under can cause mechanical failure.

Pivot 21 comprises axle 13 and lining 130.Pivot arm 20 links to each other with axle 13.Lining 130 is a low frictional torque bearing, to make things convenient for the pivot movement of pivot arm 2.

The application example of this stretcher comprises the starter generator system of belt drives, wherein originate mode many (for example when starter generator be used as alternator, stretcher on the tension side of starter generator) more violent than normal manipulation mode.

Owing to during startup of generator starting device or supercharging, need higher belt tension, therefore conventional tensioner must have too high moment of torsion output, this can be under the normal engine operating mode produces unacceptably high belt tension or near the wheel hub load-arm angle of zero degree or near the cornerite of zero degree, it causes tension control/tension on belt to die down under the normal engine operating mode, also causes higher arm motion and serviceability to reduce.

Only when belt load increased to the predeterminated level that causes pivot arm 20 joints second spring 40, stretcher of the present invention just provided additional moment of torsion output by the operation of second spring.Otherwise moment of torsion is progressively provided by first spring 41 separately.That is, during the normal running and in normal operation range, stretcher works based on the characteristic of torsion spring 41.In normal operation range, spring 40 is not compressed between pivot arm 20 and bottom 10.Therefore yet when bearing too much belt load and the stroke of arm exceeds normal operation range, joining portion 22 will come in contact with spring 40 and come in contact with base 11 thus, thus between pivot arm 22 and bottom 10 pressure spring 40.In this configuration, the spring force of spring 40 is added on the spring force of torsion spring 41.Spring 40 provides extra spring force and damping with opposing excessive load incident.Referring to Fig. 6 (a), the position of the face 45 of spring 40 under by compression state not defines the upper limit of movement of pivot arm in normal operation range.

Each

spring

40,41 provides spring force and spring rate respectively, and it has influence on the wheel hub load of stretcher.Although spring 41 provides active force directly to influence damping because of it to damping boots 15, the damping boots also provide the minimum damping force of being reeled and being launched to cause by reversing of spring equally.

Exemplary spring rate has been shown in table 1.The wheel hub loading rate (hubload rate) and the damping that are used for another exemplary application have been shown in table 2.Table 2 is based on information shown in Figure 2.

Table 1: spring rate

Spring	Spring rate
Spring	Spring rate	Spring
41	0.2Nm/deg	Spring
41	0.2Nm/deg	Spring
40	823N/mm	Spring

Table 2: wheel hub loading rate and damping constant

Scope	Loading rate (N/mm)	Stretcher damping (%)
Scope	Loading rate (N/mm)	Stretcher damping (%)	Normal operation range (only with spring 41)	2	56
Spreading range (with spring 40 and spring 41)	185	28	Normal operation range (only with spring 41)	2	56

Fig. 5 is the side view of torsion spring.Terminal 42 link to each other with bottom 10.Terminal 43 engage damping boots 15.

Fig. 6 (a) is the side cross-sectional view of second spring.Recess 44 receives pin 14.Pin 14 remains on spring 40 on the bottom 10, referring to Fig. 4.Face 45 and face 46 are positioned on the two ends of spring 40.

Face

45,46 is normally smooth, still can comprise with joining portion 22 and base 11 engaging needed Any shape.

Fig. 6 (b) is the plan view of second spring.Recess 44 is shown having classification shape (graduated form), promptly has first and second diameters so that complete joining pin 14, and does not have the interference that engages with spring output.This prevents that spring 40 from withdrawing from the bottom in pivot arm 20 and breaking away from bottom 10 at 10 o'clock.

Fig. 7 is the perspective view of damping boots.Damping boots 15 comprise the friction material 150 with predetermined coefficient of friction.Friction material 150 engaging surfaces 23 are referring to Fig. 4.Friction material 150 links to each other with main body 151.

The end 43 of receiving part 152 combined springs 41.The end 43 of spring 41 at two points, be receiving part 152 on F1 and the F2.By at F1 and F2 place the damping boots being exerted pressure, spring 41 makes damping boots surface 150 apply the active force of approximate vertical to surface 23.At the loading period that reverses of spring 41, spring 41 vertically is pressed into surface 23 with damping boots 15.This usually occurs in during the pivot movement of pivot arm 20.Spring 41 reverse loading period be formed at surface 23 and the surface frictional force between 150 than the unloading of torsion spring 41 during by surface 23 and about 1 times to about 5 times of surface 150 frictional force that form.Therefore, this comprises asymmetric damping characteristic.

Fig. 8 is the cross-sectional view of damping boots.Receiving part 152 is generally U-shaped, with combined spring end 43.For the operation of stretcher, the damping boots have asymmetric damping characteristic.This means: when moving when pivot arm response belt loaded state, be applied to that damping force on the pivot arm is greater than pivot arm response belt unloaded state and be applied to damping force on the pivot arm when moving.This means: pivot arm will be resisted because of belt load increases the motion that causes, (for example when belt becomes slack) allows the motion of pivot arm to be subjected to less restriction so that load is maintained on the belt during belt load oppositely simultaneously.

Compare with the belt uninstall direction, tensioner arms the difference of the damping characteristic of the motion on the belt loading direction at about 1: 1 to about 5: 1 scope.Damping characteristic greater than 1: 1 situation under, be asymmetric damping characteristic.As mentioned above, asymmetric damping characteristic be used for load reversal on the belt wherein cause belt should be not loose part the drive system of temporary transient loose situation appears.Damping is asymmetric to be damping mechanism, i.e. the characteristics of damping boots 15, surface 23 and torsion spring 41.

Though described forms more of the present invention at this, those skilled in the art obviously can change on structure and parts relationship under the situation that does not break away from the spirit and scope of the present invention described here.

Claims (according to the modification of the 19th of treaty)

1. stretcher, it comprises:

Bottom (10);

The pivot arm (20) that is connected with the bottom pivot;

The belt pulley (30) that is connected with the pivot arm axle journal;

Be located at first biasing member (41) between bottom and the pivot arm, described first biasing member comprises the torsion spring with first biasing member axis;

Second biasing member (40), it comprises the ssible elastomeric material that is located between bottom and the pivot arm, and has the second biasing member axis with the first biasing member axis approximate vertical; And

Described second biasing member applies spring force to pivot arm on predetermined pivot arm position, to replenish the spring force of first biasing member.

2. stretcher as claimed in claim 1, it also comprises:

Be bonded on the damping member between first biasing member and the pivot arm; And

Described damping member provides asymmetric damping characteristic.

3. stretcher as claimed in claim 2, it also comprises the damping member with the pivot arm frictional engagement.

4. stretcher, it comprises:

Bottom (10);

The pivot arm (20) that is connected with the bottom pivot;

The belt pulley (30) that is connected with the pivot arm axle journal;

Be located at first biasing member (41) between bottom and the pivot arm;

Be bonded on the damping member (15) between first biasing member and the pivot arm;

Described damping member provides asymmetric damping characteristic to stretcher;

Second biasing member (40), it comprises the ssible elastomeric material that is located between bottom and the pivot arm; And

5. stretcher as claimed in claim 4, wherein, asymmetric damping characteristic at about 1: 1 to about 5: 1 scope.

6. stretcher as claimed in claim 4, wherein, second biasing member comprises the axis that is provided with the first biasing member axis approximate vertical.

7. stretcher, it comprises:

Bottom (10);

The pivot arm (20) that is connected with the bottom pivot;

The belt pulley (30) that is connected with the pivot arm axle journal;

Be located at first biasing member (41) between bottom and the pivot arm, described first biasing member applies spring force to pivot arm on first operating range;

Described second biasing member applies spring force to pivot arm on predetermined pivot arm position, described predetermined pivot arm position is located in the operating range, and second biasing member replenishes the spring force of the first spring biasing member when exceeding this predetermined pivot arm position.

8. stretcher as claimed in claim 7, it also comprises:

Damping member provides asymmetric damping characteristic.

9. stretcher as claimed in claim 8, it also comprises the damping member with the pivot arm frictional engagement.

10. stretcher as claimed in claim 8, wherein, asymmetric damping characteristic at about 1: 1 to about 5: 1 scope.

11. stretcher as claimed in claim 7, wherein, second biasing member comprises the axis that is provided with the first biasing member axis approximate vertical.

12. stretcher as claimed in claim 11, wherein, first biasing member comprises torsion spring.

Claims

1. stretcher, it comprises:

Bottom (10);

The pivot arm (20) that is connected with the bottom pivot;

The belt pulley (30) that is connected with the pivot arm axle journal;

Be located at second biasing member (40) between bottom and the pivot arm, it has the second biasing member axis with the first biasing member axis approximate vertical; And

2. stretcher as claimed in claim 1, wherein, second biasing member comprises ssible elastomeric material.

3. stretcher as claimed in claim 1, it also comprises:

Described damping member provides asymmetric damping characteristic.

4. stretcher as claimed in claim 3, it also comprises the damping member with the pivot arm frictional engagement.

5. stretcher, it comprises:

Bottom (10);

The pivot arm (20) that is connected with the bottom pivot;

The belt pulley (30) that is connected with the pivot arm axle journal;

Be located at first biasing member (41) between bottom and the pivot arm;

Be located at second biasing member (40) between bottom and the pivot arm; And

6. stretcher as claimed in claim 5, wherein, second biasing member comprises ssible elastomeric material.

7. stretcher as claimed in claim 5, wherein, asymmetric damping characteristic at about 1: 1 to about 5: 1 scope.

8. stretcher as claimed in claim 5, wherein, second biasing member comprises the axis that is provided with the first biasing member axis approximate vertical.

9. stretcher, it comprises:

Bottom (10);

The pivot arm (20) that is connected with the bottom pivot;

The belt pulley (30) that is connected with the pivot arm axle journal;

Be located at second biasing member (40) between bottom and the pivot arm; And

Described second biasing member applies spring force to pivot arm on predetermined pivot arm position, described predetermined pivot arm position is located in the operating range, and is exceeding this predetermined pivot arm position, and second biasing member replenishes the spring force of the first spring biasing member.

10. stretcher as claimed in claim 9, it also comprises:

Described damping member provides asymmetric damping characteristic.

11. stretcher as claimed in claim 10, it also comprises the damping member with the pivot arm frictional engagement.

12. stretcher as claimed in claim 10, wherein, asymmetric damping characteristic at about 1: 1 to about 5: 1 scope.

13. stretcher as claimed in claim 9, wherein, second biasing member comprises the axis that is provided with the first biasing member axis approximate vertical.

14. stretcher as claimed in claim 13, wherein, second biasing member comprises wind spring.

15. stretcher as claimed in claim 14, wherein, first biasing member comprises torsion spring.